What is Positive Psoas Sign – Acute Appendicitis
Acute appendicitis refers to acute inflammation of the appendix, typically due to an obstruction of the appendiceal lumen. In both children and adults, it is the most common cause of acute abdomen requiring emergency surgical intervention.
The characteristic features of acute appendicitis are:
- Periumbilical abdominal pain that migrates to the right lower quadrant (RLQ)
- Anorexia (loss of appetite)
- Hamburger sign: If there is no loss of appetite, appendicitis is unlikely.
- Nausea
- Fever
- RLQ abdominal tenderness.
Positive Psoas Sign Acute Appendicitis
Clinical signs of appendicitis
- McBurney point tenderness (RLQ tenderness)
- Tenderness at the junction of the lateral third and medial two-thirds of a line drawn from the right anterior superior iliac spine to the umbilicus
- This point corresponds to the location of the base of the appendix.
- RLQ guarding and/or rigidity
- Rebound tenderness (Blumberg sign), especially in the RLQ
- Rovsing’s sign: RLQ pain elicited on deep palpation of the LLQ [7]
- Psoas sign
- Can be elicited on flexing the right hip against resistance
- RLQ pain may be elicited on passive extension of the right hip
- Obturator sign: RLQ pain on passive internal rotation of the right hip with the hip and knee flexed
- Hyperesthesia within Sherren triangle: formed by the anterior superior iliac spine, umbilicus, and symphysis pubis
- Lanz point tenderness: at the junction of the right third and left two-thirds of a line connecting both the anterior superior iliac spines
- Pain in the Pouch of Douglas: pain elicited by palpating the rectouterine pouch on rectal examination
- Baldwin sign: pain in the flank when flexing the right hip (suggests an inflamed retrocecal appendix)
Positive Psoas Sign Acute Appendicitis
Diagnosis
Laboratory testing:
Although limited in their ability to differentiate appendicitis from other causes of abdominal pain, the following studies are typically obtained in children suspected to have appendicitis:
- White blood cell count (WBC): Will be elevated
- Differential with calculation of the absolute neutrophil count (ANC): Will be elevated
- C-reactive protein (CRP): Will be elevated
- Urinalysis: mild pyuria may be present. Also to rule out urinary tract infection
Imaging studies:
- Abdominal ultrasonography: is inexpensive, safe, and widely available. Diagnostic accuracy, reported to range from 71 to 97% and is highly dependent on operator skill. Ultrasonography is especially useful in women who are pregnant or of childbearing age, and in children. Major advantages to ultrasonography include non-invasiveness, short acquisition time, lack of radiation exposure, and potential for discovering other causes of abdominal pain (e.g., ovarian cysts, ectopic pregnancy, tubo-ovarian abscess).
- Abdominal CT with IV contrast: is more precise than ultrasonography and more reproducible from hospital to hospital. It has a diagnostic accuracy rate for acute appendicitis of 93 to 98%.
Positive Psoas Sign Acute Appendicitis
Management
Conservative management, which includes bowel rest, antibiotics, and analgesics, is indicated in patients with an inflammatory appendiceal mass (phlegmon) or an appendiceal abscess because surgical intervention is associated with a higher risk of complications in these patient groups.
The current standard of management of acute appendicitis is emergency appendectomy (open or laparoscopic) and broad-spectrum antibiotics.
Interval appendectomy 6–12 weeks after resolution of the acute episode can be performed in these patients to prevent a recurrence.
Positive Psoas Sign Acute Appendicitis
How to look for Psoas sign
The technique for detecting the psoas sign is carried out on the patient’s right leg. The patient lies on his/her left side with the knees extended. The examiner holds the patient’s right thigh and passively extends the hip. Alternatively, the patient lies on their back, and the examiner asks the patient to actively flex the right hip against the examiner’s hand.
The psoas sign. Pain on passive extension of the right thigh. Patient lies on left side. Examiner extends patient’s right thigh while applying counter resistance to the right hip (asterisk).
If abdominal pain results, it is a “positive psoas sign”. The pain results because the psoas borders the peritoneal cavity, so stretching (by hyperextension at the hip) or contraction (by flexion of the hip) of the muscles causes friction against nearby inflamed tissues.
In particular, the right iliopsoas muscle lies under the appendix when the patient is supine, so a positive psoas sign on the right may suggest appendicitis.
A positive psoas sign may also be present in a patient with a psoas abscess. It may also be positive with other sources of retroperitoneal irritation, e.g. as caused by hemorrhage of an iliac vessel.
Other physical examinations that helps in diagnosing acute appendicitis are Obturator’s Sign and Rovsing’s Sign.
Positive Psoas Sign Acute Appendicitis
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Positive Psoas Sign Acute Appendicitis